I have just replaced my BeoVision MkIII with a MkIV with a DVB-HD module and here are my findings after a couple of hours use:
The screen is very revealing of the quality of the source. It is extremely easy to judge the quality of the signal.
The picture still looks good much further off-axis than on the MkIII.
The picture looks softer and more plasma like, but it might be related to the sharpness setting.
The Blu ray drive is a little slow and noisy during the start up phase, but after that, everything is OK. A good quality picture and a really nice menu that makes it easy to navigate and change settings.
The DVB-HD module is fast compared to my previous Samsung set-top box, with a good and quick program list.